ProgressBa滚动体在安卓程序中使用也比较多。
ProgressBa的几个常用的属性和方法
android:max="200" 滚动条最大值
android:progress="0" 滚动条当前值
android:visibility="visible" 滚动条是否可见
setProgress(int) 最大值
XML代码
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <ProgressBar android:id="@+id/progressBar" style="?android:attr/progressBarStyleHorizontal" android:layout_width="match_parent" android:layout_height="wrap_content" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/tv_progress_num"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="下载" android:onClick="download"/> </LinearLayout>
JAVA代码
public class ProgressActivity extends AppCompatActivity { private TextView tv_progress_num; private ProgressBar progressBar; @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_progress); progressBar = (ProgressBar) findViewById(R.id.progressBar); tv_progress_num = (TextView) findViewById(R.id.tv_progress_num); } /** * ANR * application not responsing 应用程序未响应 * why:在主线程中执行了耗时的操作 * how:在子线程中执行耗时操作 * @param view */ public void download(View view){ new MyThread().start(); } Handler handler=new Handler(){ //接受消息，更新UI界面 @Override public void handleMessage(Message msg) { super.handleMessage(msg); int i=msg.what; tv_progress_num.setText(i+""); } }; class MyThread extends Thread{ @Override public void run() { super.run(); for (int i = 0; i <=100 ; i++) { progressBar.setProgress(i); //在子线程中发消息 handler.sendEmptyMessage(i); try { Thread.sleep(100); } catch (InterruptedException e) { e.printStackTrace(); } } } } }
